In order to determine the temperature value reached by a mixture of food inside the cylinder, the latter comprises a heat sensor, which, for construction reasons, is normally positioned in correspondence with the vertical rear wall forming the bottom of the cylinder, mostly arranged horizontally (with a horizontal axis).
The disadvantage of this known technique is mainly represented by the action of the mixer which, upon rotating, pushes the food mass towards the front area of the cylinder. In this case, and above all in the processing of small quantities of food, the sensor, situated on the outer wall of the cylinder, remains uncovered, i.e. it does not come into contact with the mixture, thus considerably misrepresenting the reading of the heat level reached by the latter.
Another solution is the one disclosed in U.S. Pat. No. 7,047,758 in which the temperature sensor is placed directly below the charging duct of the products; this solution has the drawback of altering the measurement of the temperature sensor, since the mass of the charged product comes into contact with the sensor when it has not yet been cooled by the cylinder.